1. Field of the Invention
The present invention relates to a Web page viewing apparatus, and in particular, to a Web page viewing apparatus with which a viewer can view Web pages with high operability without being affected by a communication failure on the Internet.
2. Description of the Related Art
In recent years, inspection of information via the Internet has become popular. For example, a user instruction, a maintenance manual, and the like for a machine sold by a company appear on a Web page of the company such that service persons of service dealers for the machine or maintenance personnel of customers can perform maintenance for the machine reading the user instruction, the maintenance manual, and the like. In addition, a parts list of a sold machine also appears on a Web page such that service dealers or customers can place an order for parts necessary for maintenance and improvement (for example, see JP-A-2002-24225). In provision of information using such a Web page, contents appearing on the Web page are often updated, and a person viewing the Web page is required to always access the Web page to obtain latest information in order to have the latest information displayed on the Web page.
However, a viewing apparatus in accordance with a conventional Web page viewing technique has problems as described below.
The viewing apparatus cannot read image information from a Web page server (hereinafter simply referred to as Web server) temporarily according to circumstances in locations where a communication failure on the Internet occurs such as the inside of a building, an underground floor, a space between buildings, and a mountain valley. In such a case, for example, when a person is repairing a machine while reading materials such as a user instruction, a maintenance manual, and a parts manual on a Web page, since the person cannot view the materials at will, the person cannot have an arbitrary page necessary for the repair displayed on the Web page. As a result, longer time is required for the repair.
On the other hand, usually, a personal computer is often used as a terminal for Web page viewing. In that case, a viewer inputs data with a so-called WWW browser in order to read character information and image information of a Web page from a Web server. In general, when the viewer views the Web page using this WWW browser, screen information (including character information and image information) at the time of the viewing is automatically stored in a predetermined temporary memory in the personal computer for each screen in an order of viewing. Thereafter, when the viewer performs a “return” operation, the image information stored in the temporary memory is read out and displayed on the Web page in an order opposite to the order of viewing.
Therefore, when the viewer views the Web page using the conventional WWW browser as described above, in general, even if data (image information) cannot be read from a Web server according to circumstances, the image information stored in the temporary memory can be displayed. Thus, the viewer can have image information viewed once displayed on the Web page again. However, the image information can only be displayed in the order opposite to the order of viewing, and the temporary memory has a limited capacity and adopts a storage system in which, when a storage capacity is fully used, data stored earlier is deleted every time data is stored (first-in first-out). Consequently, in the case of an image including systematically described contents like materials such as a user instruction, a maintenance manual, and a parts manual, there is a problem in that it is difficult to directly designate a page of the materials, which the viewer desires to view, and have the image displayed on the Web page, and operability is low.
When the viewer designates image information, which the viewer desired to save, and stores the image information in the personal computer in a form of a file but cannot read data from the Web server due to a communication failure on the Internet, the viewer can also have the image information, which is saved in the form of a file, displayed on the web page offline. However, even in this case, the viewer has to judge which of the image information saved in the form of a file and latest image information on the Web page (data on the server) is new and old, that is, the viewer has to compare dates of update of the image information saved in the form of a file and the latest image information on the Web page. Therefore, the image information saved in the form of a file cannot be matched with the image information on the Web page. Consequently, the viewer needs to read the latest information from the Web page every time the viewer views the Web page. Thus, there is also a problem in that operability is low because an operation for reading the latest information is troublesome, and when a data capacity of the image information at that point is large, it takes time to download the image information.